NgModelController provides API for the ngModel directive. The controller contains services for data-binding, validation, CSS updates, and value formatting and parsing. It purposefully does not contain any logic which deals with DOM rendering or listening to DOM events. Such DOM related logic should be provided by other directives which make use of NgModelController for data-binding to control elements. Angular provides this DOM logic for most input elements. At the end of this page you can find a custom control example that uses ngModelController to bind to contenteditable elements.

You should use $setViewValue and then, as highlighted above, due to the nature of the API you need to call $render to update the view: